Arylaminomethine compounds



. This, invention relates fiatentecl July 18, 1950 UNITED/STATES I M l IARYLAMTNOMETHINE CoMP oU Ds f Edward B. Knott, Harrow-Wealdstone,England,

assignor to Eastman Kodak'Gompany, Rochester, N. Y., a corporation'ofNewJersey N Drawing. Application b are 26, 1946, Se-

rial No. 706,053. 1946 to arylaminomethine compounds and to a processfor. preparing the same. i

. .It is known that certain arylaminomethine compounds can .be preparedby condensing cyclic compounds having an iutracyclic ketomethylene groupwith diarylformamidines. Thus, -ani1inomethylene-3-ethylrhodanine and4-anilinomethy1ene-3-methy1-1-phenyl-5-pyrazolone can" be prepared bycondensing 3-ethylrhodanine or 3- methyl-l-phenyl-5-pyrazolone withdiphenylformami'dine. See Dains et a1.,J. AmQChem.

'Soc'. 31, v1153 (1909); 35, 959 (1913); as, 1841 s'olaims. (Cl 260 240)In Great'Britain January 19,

.p aettoatsayl, e-naphthyl, penaphthyl, etc.

and R2 represents an alkyl group (substituted or unsubstituted), e. g.methyl, ethyl, n-propyl, isobutyl, n-butyl, l3-ethoxyethyl, allyl,benzyl, etc.

The cyclic compounds ,containing the intracyclic ketomethylene group canbe represented by the following general formula:

in; IX

'wiierein'oiebreseias an oxygen or a sulfur atom and X represents thenon-metallic atoms neces- "sary to -concpl'ete a cyclic nucleuscontaining from 5 to6' atoms in the ring.

Typical compounds represented by the above general FormulaTI lar e:'thiazolones (such as isothiohydantoin) thiazolidones *(e. g.4-thiazolidone), thiothiazolediones (e. g. 2-thio-2,4(3,5)-

liberated in the diarylformamidine process and Y the amine may have adetrimental effect. my new process, an alcohol is liberated during theprocess.

-It is, accordingly, an object of myinvention to provide an improvedprocess for preparing arylaminomethine compounds. to providearylaminomethine compounds. objects will become apparent hereinafter.

In accordance with my invention, I prepare arylaminomethine compounds bycondensing an alkylisoformanilide (i; e. a N-arylformimino ether) with acyclic compound-containing from 5 to 6 atoms in the cyclic nucleus andcontaining an intracyclic ketomethylene group (..CH2'CO-) orthioketomethylene group (-CH2CS). I have also found that anils canbe-prepared by condensing an ralkylisoformanilide with. polycyclicphenols in which at'leastone of the positions ortho and para to thephenolic hydroxyl group is not substituted, i. e. a polycyclic phenolcontaining a -CH= group in one orboth of the positions ortho and para tothe phenolic hydroxyl group.

The alkylisoformanilides which I employ in practicing my invention canbe represented by the following general formula:

Other wherein R1 represents an aryl group (substituted A further objectis thiazolediones, i. e. rhodanines), dithiothiazolediones (e. g.2,4-dithio-2,4(3,5)-thiazolediones, i. e. thiorhodanines), barbituricacids, thiobarbituric acids, 'oxa'zolones, thio-oxazolediones (e. g.2-thio-2,4 (3,5) -oxazolediones) iminazolones, iminazolediones(hydantoins) e. g. 2-thio-2,4(3,5)-

iminazoledione, oxydihydroquinoxalines, dihydroide, indandioneAtetronicacid, ketodihydrothioor unsubstituted), e. g. phenyl, p-chlorophenyl,

'nap'hthenes (e. g. thioxindoxyl), indoXyl, benZO- morpholones,ZA-dihydroxyquinoline (d-hydroxycarbostyrill'eto ticing -rnyinventioncan be represented by the following general formula:

'The polycyclic phenols which I employ in pracwherein R3 and R4represent a hydrogen atom or a monovalent organic radical and nrepresents a positive integerof from 1 to 2, and D represents thenon-metallic atoms necessary to complete a carbocyclic or heterocyclicnucleus.

Typical polycyclic phenols represented by the above" "general Formula"-111" are B-naphthol, ariapht-h'ol, anthranolg 4-hydroXy-2-methylnaph-'tha} 1" :Z'A 5- thi'az ole, 2-phenanthrol, etc. ""The-condenjsatiorisof the alkylisoformanilides withfthe' compounds' containing theintracyclic ketomethylene or thioketomethyl'ene group can becarriedoutbyheating, with or without a solvent, advantageously at to 200 C.Certain of the 5-pyrazolones condense with the alkylisoformanilidesreadily on a steam bath while other ketomethylene compounds requirefusion at 120 to 180 C. or higher.

In the case of condensations of the polycyclic phenols withalkylisoformanilides, the condensations are best carried out by fusionat an elevated temperature, advantageously between 100 and 200 C. Forthis condensation, it is not necessary to commence with theN-arylformimino ether (alkylisoformanilide) since, if the condensationis carried out at 120 C. or above, the N- arylformimino ether can beiormed in situ. Thus, for example, the polycyclic phenol can be fused.with a mixture of a primary aromatic .amine (e. g. aniline,p-chloroaniline, p-methoxyaniline, etc.), and an excess of an alkyl.orthoformate (e. g. ethyl orthoiormate, n-propyl orthoformate. n-butylorthoformate, isobutyl orthoformate. etc.) or a diarylformamidine(diphenylformamidine, etc.) and an alkyl orthoformate. Both of theaforesaid mixtures give the N-arylform-imino ether in situ, as shown byClaisen, Ann. 287, 365 (1895).

Polycyclic phenols containing both a freeortho and para position willusually give rise to amixture of anils. Monocyclic phenols do notcondense readily and phenol, itself, not at all. B-naphthols containinga substituent in the l-position do not condense, but these substancesare not polycyclic phenols in which at least one of the positions ,orthoand para to the phenolic hydroxyl group is unsubstituted.

The following examples will serve to illustrate further the manner ofpracticing my invention.

Example 1 .4-anilinomethine-3 -methyl-1 phenyl-5-pyrazolone FCH H Q HIExample 2.--anilinomethine-3-ethyZ-4-ket0 z-thiotetrahydro-owazole3-ethyl -4- keto 2 thiotetrahydr0-0XaZole(3- ethyl-2-thio-2 ,4(3,5)-oxazoledione) (1.45 g.) and ethylisoformanilide (1.5 g.) were fused for30 minutes at 150 C. Ethyl .alcohol was evolved and crystals of theanilinomethine compound formed. After cooling the solid anilinomethinecompound was recrystallized from ethyl alcohol in which t is spa y olube. thu .f rmine pale yellow needles which melted at 235 .C.

Example 3.(2 -hydromy-1 -naphthylidene) aniline C H=N- 0 0H;

fl-Naphthol (14.4 g.) and ethylisoformanilide (14.9 g.) were fused at160 C. for 30 minutes at the end of which time the evolution of ethylalcohol .had ceased. Methyl alcohol (5 cc.) was added to the melt whichwas then chilled. Yellow plates (17 g.) of the naphthylidene compoundcrystallized. Recrystallized from methanol, the naphthylidene compoundmelted at 92 C.

Example 3a.(Z-hydromy-I-naphthylidene) aniline fi-Naphthol (14.4 g.),diphenylformamidine (4 g.) and ethyl orthoformate (3 g.) were fused atC. for 30 minutes and then at C. for 30 minutes. On cooling the yellowoil was shaken with light petroleum ether which caused completesolidification. From methyl alcohol the naphthylidene compound formedyellow plates which melted at 92 C.

Example 4.--2-hydromy-1-naphthylidenep-anisidz'ne fi-Naphthol (5.76 g.),ethyl orthoformate (5.92 g.) and p-anisidine (4.92 g.) were fused at 150C. for 60 minutes. A little methyl alcohol was added to the cooled melt;on scratching the whole solidlfied. From methyl alcohol thenaphthylidene compound was obtained as bright yellow needles melting at111 C.

Example 5 .9-hydroa:y-10-anthrylidineaniline CH=N- CQH Anthranol(anthrone) (3.48 g.) and ethylisoformanilide (3 g.) were fused at C. for60 minutes. Ethyl alcohol (10 cc.) was added to the orange red melt andthe whole was chilled. A crystalline solid (49 g.) separated. Fromacetic acid, the anthra'niline compound formed garnet red crystals,melting at 204 C. Its sodium salt gave a brilliant red solution.

9ehydroxy-IO-anthraldehyde was obtained by dissolving the above anil (2g.) in boiling acetic acid (20 cc.) and adding concentrated hydrochloricacid (4 00.). A brilliant red color developed which quickly faded; oncooling colorless crystals of the aldehyde were deposited. From benzenethey formed creamy fiat needles, melting at 230 C. onward.

Example 6.-.4'-hydroacy-.2-methylnaphtha- 1',2',4,5-thfiaeoZe-3-aldehydeAnil.

CH=NC5H5 4-hydroxy-2-methylnaphtha-1,2,4,5-thiazole (10.95 g.) andethylisoformanilide g.) were fused at 170C. for 60 minutes. On coolingthe deep orange melt solidified. It was ground with ethyl alcohol,collected on a filter and washed with ethyl alcohol (13.2 g.). Frombenzene the anil was obtained as orange needles melting at 228 C.

The corresponding aldehyde was obtained as in the previous Example 5,using 1,4-dioxane as a solvent instead of acetice acid. From ethylalcohol, the aldehyde was obtained as greenish needles melting at 160 C.The aldehyde had the following formula:

CHO

Any of the anils obtained, in accordance with my invention, can behydrolyzed to give the corresponding aldehyde as shown above. The anilscan be employed in rubber compounding.

In the same manner shown in the foregoing examples, other of theketomethylene compounds and polycyclic phenols can be condensed withalkylisoformanilides.

The 4-hydroxy-2-methylnaphtha-1', 2,4,5- thiazole employed above can beprepared as described in my copending application Serial No. 584,736,filed March 24, 1945 (now United States Patent 2,476,669, dated July 19,1949).

What I claim as my invention and desire to be secured by Letters Patentof the United States is:

1. A process for preparing an arylaminomethine compound comprisingcondensing, at a temperature of from 100 to 200 C., analkylisoformanilide selected from those represented by the followinggeneral formula:

wherein R1 represents an aryl group selected from 6 1 to 7 carbon atoms,with a nitrogen heterocyclic ketomethylenecompound selected from thoserepresented by the following general formula:

wherein X represents the non-metallic atoms necessary to complete aheterocyclic compound selected from the group consisting of4-keto-2-thiotetrahydro-oxazoles and 5-pyrazolones.

2. A process for preparing an arylaminomethine compound comprisingcondensing, at a temperature of from to 0., an alkylisoformanilide inwhich the alkyl group is a primary alkyl group containing from 1 to 4carbon atoms with a 4- ketc-2-thiotetrahydro-oxazole.

3. A process for preparing an arylaminomethine compound comprisingcondensing, at a temperature of from 120 to 180 C., ethylisoformanilidewith 3-ethyl-4-keto-2-thiotetrahydro-oxazole.

,4. A process for preparing an arylaminomethine compound comprisingcondensing, at a temperature of 100 to 200 0., an alkylisoformanilide inwhich the alkyl group is a primary alkyl group containing from 1 to 4carbon atoms with a 5- pyrazolone,

5. A process for preparing an arylaminomethine compound comprisingcondensing, at a temperature of 100 to 200 C., ethylisoformanilide with3- methyl- 1 -phenyl- 5 -pyrazolone.

EDWARD B. KNCTT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,165,339 Brooker July 11, 19392,241,238 Brooker May 6, 1941 FOREIGN PATENTS Number Country Date334,706 Great Britain Sept. 11, 1930 404,997 Great Britain Jan. 22, 1934412,309 Great Britain June 28, 1934 432,628 Great Britain July 23, 1935

1. A PROCESS FOR PREPARING AN ARYLAMINOMETHINE COMPOUND COMPRISINGCONDENSING, AT A TEMPERATURE OF FROM 100 TO 200*C., ANALKYLISOFORMANILIDE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWINGGENERAL FORMULA: